A Thin Film Transistor (TFT) of a liquid crystal display device manufactured with Low Temperature Poly-silicon (LTPS) generally has a top gate structure, and therefore a light shielding layer needs to be provided to block backlight.
A 9-mask top gate process is generally adopted to manufacture an LTPS liquid crystal display, in which the light shielding layer is made of the metal molybdenum (Mo). Since there is a risk of discharge during chemical vapor deposition (CVD) on the entire layer of metal, it is necessary to etch the entire layer of metal to form a pattern before performing the CVD. Thus, when the light shielding layer is made of Mo, it cannot be etched with an active layer (for example, which is made of poly-silicon (p-Si)) by using a same mask. The use of amorphous-silicon (a-Si) to form a light shielding layer can solve this problem because the light shielding layer made of a-Si can be etched with the active layer made of p-Si by using a same mask, thereby reducing one mask and simplifying the previous 9-mask process as an 8-mask process. Therefore, production costs will be greatly reduced.